We will solve this step by step to determine cost of goods sold (COGS) for the September 30 sale and ending inventory using the First-In, First-Out (FIFO) method.

---

Step 1: Track Inventory Changes and COGS under FIFO

Since we are using FIFO, the oldest inventory is sold first. Below is the sequence of events:

• Beginning Inventory (Sep 1):
  31 units @ $22 each = 31 × 22 = $682

• Sep 5 Sale: 18 units

  • Use 18 units from beginning inventory (31 units @ $22).

  • COGS = 18 × 22 = $396

  • Remaining Inventory after Sep 5:
    31 - 18 = 13 units @ $22 each = $286

• Sep 17 Purchase: 33 units @ $24 each

  • Add 33 units @ $24 = 33 × 24 = $792

  • Total Inventory after Sep 17:
    13 units @ $22 = 286
    33 units @ $24 = 792
    Total = 13 + 33 = 46 units
    Total value = 286 + 792 = $1,078

• Sep 30 Sale: 33 units

  • Follow FIFO (sell older inventory first):

    • 13 units @ $22 = 13 × 22 = $286
    • Remaining 33 - 13 = 20 units taken from new batch (33 units @ $24): 20 × 24 = $480

  • COGS for Sep 30 Sale = 286 + 480 = $766

---

Step 2: Calculate Ending Inventory on September 30

After the sale on Sep 30, we had 33 units and sold 33 units.
The inventory now looks like this:

• Used 13 units @ $22

• Used 20 units from 33 units @ $24
  Remaining Inventory = 33 - 20 = 13 units @ $24

  Total value of ending inventory = 13 × 24 = $312

---

Answers

a. Cost of Goods Sold (COGS) for Sep 30 Sale = $766
b. Ending Inventory on Sep 30 = $312

---

Do you want more details or have further questions?

Here are 5 related questions:

1. What is the difference between FIFO and LIFO?
2. How does perpetual inventory differ from periodic inventory?
3. How would COGS change if LIFO were used?
4. Why is FIFO commonly used for perishable goods?
5. How can inflation impact FIFO-based inventory valuation?

Tip: FIFO generally results in lower COGS and higher profits during periods of rising prices.